The Teradyne PXI Express-based High Speed Subsystem (HSSub) addresses defense and aerospace ATE requirements that are common to most recent designs including buses with increasing speeds, protocol complexity, big data handling and processing demands. HSSub further accommodates the need for lower latency interaction with the unit under test. HSSub is designed for integration into existing or future test systems with the ease of a single LXI instrument. Alternatively, it can be used in a standalone role for test development or as a bench-top tester. HSSub provides the most economical approach for developing and sustaining test capability for the range of test problems facing engineers today.